<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        aside {
            float: right; /* 或 float: right; */
            width: 25%; /* 或其他适当的宽度 */
        }
    </style>
</head>
<body>

<div>
    <aside>
        <nav>导航内容1</nav>
        <nav>导航内容2</nav>
        <nav>导航内容3</nav>
    </aside>
    <h1>ss</h1>
</div>

<!--绘制线-->
<hr style="height: 10px; background-color: blue"/>

<div>
<mark style="background-color: red; color: white">这是</mark>1个mark标签
</div>

</body>
</html>